Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q07644 (polypeptide)
 72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lobster arginine kinase [EC 2.7.3.3] contains 2 tryptophanyl residues and 9 methionyl residues. The whole carboxymethylated protein was first subjected to CNBr cleavage and the resulting fragments were isolated by gel filtration and other experimental approaches. One fragment, CB5, which contains 60 residues including the two tryptophanyl residues and two of the five cysteinyl residues of the protein, was characterized and the results are reported inthis paper. The overall strategy for the establishment of the complete sequence of this fragment was based on the use of three types of peptides: (a) whole cyanogen bromide peptide CB5 which was partially characterized by automatic Edman degradation using a sequencer: 42 steps were performed out of 60 residues, (b) tryptic peptides of CB5, (c) peptides formed by cleavage of S-carboxymethylated arginine kinase (whole protein) at the two tryptophanyl residues with BNPS-skatole. The complete amino acid sequence of the CNBr polypeptide (CB5) which contains the two tryptophanyl residues of the whole protein was established.
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PMID:Amino acid sequence of a cyanogen bromide fragment containing the two tryptophanyl residues of lobster arginine kinase (Homarus vulgaris). 1 71

A reinvestigation of the modification reactions of alpha-chymotrypsin with phenacyl bromide was carried out. Results conclusively demonstrate that the chemically and physically different modified enzymes prepared at pH 4 and at pH 7 both contain the phenacyl group at methionine-192 in the sulphonium salt form. Evidence to suppoort this conclusion derives from 13C nuclear-magnetic-resonance spectroscopic observations on [methylene-13C]phenacyl-enriched enzymes. More conclusively, the methionine-192-containing C-chain, derived by performic acid oxidative cleavage of radioactively-labelled enzyme prepared at pH 7, was shown to contain the phenacyl moiety and to undergo dealkylation by 2-mercaptoethanol with loss of this moiety. In addition, thermolytic cleavage of the high-pH enzyme results in fragmentation of the polypeptide chain in a fashion analogous to model reactions of phenacylmethionyl dipeptides and other methionine-192 sulphonium salts. A rationalization of the unusual nature of the high-pH phenacyl-modified enzyme based on the irreversible formation of stable conformation in which the phenacyl moiety is rigidly located in interior regions of the enzyme is presented and discussed.
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PMID:Evidence for a pH-dependent irreversible formation of a stable conformation of phenacyl-alpha-chymotrypsin. 2 56

Toxin I from Anemonia sulcata, a major component of the sea anemone venom, consists of 46 amino acid residues which are linked by three disulfide bridges. The [14C]carboxymethylated polypeptide was sequenced to position 29 by automated Edman degradation. The remaining sequence was determined from cyanogen bromide peptides and from tryptic peptides of the citraconylated [14C]carboxymethylated toxin. Toxin I is homologous to toxin II from Anemonia sulcata and to anthopleurin A, a toxin from the sea anemone Anthopleura xanthogrammica. These toxins constitute a new class of polypeptide toxins. No significant homologies exist with toxin III from Anemonia sulcata nor with known sequences of neurotoxins or cardiotoxins of various origin.
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PMID:Amino-acid sequence of toxin I from Anemonia sulcata. 2 53

Horseradish peroxidase C dominates quantitatively among the isoperoxidases of horseradish root and has an isoelectric point close to 9. It consists of a hemin prosthetic group, 2 Ca2+ and 308 amino acid residues, including 4 disulfide bridges, in a single polypeptide chain that carries 8 neutral carbohydrate side-chains. The molecular weight of the polypeptide chain is 33890. Assuming an average carbohydrate composition of (GlcNAc)2, Man3, Fuc, Xyl for each carbohydrate chain, the molecular weight of native horseradish peroxidase C is close to 44 000. Cyanogen bromide fragments of reduced and carboxymethylated apo-peroxidase were purified by a combination of gel filtration and isoelectric focusing in urea, and cystine-containing tryptic fragments of apo-peroxidase were purified by gel filtration followed by disulfide cleavage and rechromatography at the initial conditions. The present paper discusses (a) isoelectric points and charge distribution within the native protein, the apoprotein and the cyanogen bromide fragments, (b) a buried pyrrolidonecarboxylyl amino terminus, (c) heterogeneity at the carboxyl terminus, and (d) a possible domain structure, likely from partial tryptic digestion.
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PMID:Amino acid sequence studies of horseradish peroxidase. Amino and carboxyl termini, cyanogen bromide and tryptic fragments, the complete sequence, and some structural characteristics of horseradish peroxidase C. 3 13

The glial fibrillary acidic protein and an immunologically active cyanogen bromide peptide were purified by immunoaffinity chromatography from 8 M urea extracts of brain filament preparations isolated from bovine white matter according to Norton's procedure. The protein accounted for approximately 30% of the total protein in this preparation and for the largest fraction in the 50 000 molecular weight range. The fraction not absorbed to the immuno-Sepharose column reacted with neurofilament antisera by double immunodiffusion. On sodium dodecyl sulfate gel electrophoresis the main bands in the non-adsorbed fraction were at 74 000 daltons and above 100 000. Several bands were seen in the 50 000 molecular weight range. It is concluded that glio- and neurofilaments co-purify together in Norton's procedure and that neurofilaments are probably heterogeneous in polypeptide composition.
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PMID:Astroglial and axonal proteins in isolated brain filaments. I. Isolation of the glial fibrillary acidic protein and of an immunologically active cyanogen bromide peptide from brain filament preparations of bovine white matter. 3 23

Cytochromes c have been used as antigens in a murine T-lymphocyte proliferation assay in order to characterize the nature of determinants whose recognition is under immune response (Ir) gene control. The cytochromes are advantagous as antigens because 1) they have well-characterized primary and tertiary structures, 2) they are antigenically simple, differing from mouse cytochrome c at only a small number of amino acid residues, and 3) there exist a large number of evolutionary variants which can be used to locate antigenic sites by cross-stimulation. In the present studies, the T-lymphocyte proliferative response to pigeon cytochrome c was shown to be under the control of two complementing major histocompatibility (MHC)-linked Ir genes in mice of the H-2a and H-2k haplotypes. Mice of the H-2b, H-2d, H-2p, H-2q, H-2s, and H-2u haplotypes were low or nonresponders. Complementation was demonstrated by showing that an F1 hybrid between two nonresponder recombinant strains, B10.A(4R) and B10.A(5R), could respond to pigeon cytochrome c. The determinant on the cytochrome recognized in this immune response was located to the C-terminal portion of the molecule around residues 89 and/or 100. This was shown by the failure of closely related cytochromes from the Pekin duck and chicken to cross-stimulate T lymphocytes immune to pigeon cytochrome; position 89 and 100 carry the only residues different from those in mouse cytochrome c that are unique to pigeon cytochrome among the three bird cytochromes tested. This localization was further substantiated by demonstrating that the cyanogen bromide cleavage-fragment (residues 81-104) from pigeon cytochrome, but not the same fragment from Pekin duck cytochrome, was as good a stimulant of T cells immune to the whole molecule as the intact cytochrome. These results identify the immunogenic site on the molecule as one which differs from mouse cytochrome c by only one or two amino-acid residues. Thus, T-cell immune responses, which are under MHC-linked Ir gene control, are as capable as antibody responses of recognizing subtle differences in protein structure. However, the ability of T cells to respond equally well to stimulation with polypeptide fragments or with the whole molecule suggests either that T-cell recognition involves certain differences from B cell recognition or that in some cases the fragments possess a similar spatial structure to that of the corresponding segment in the native protein.
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PMID:Genetic control of the T-lymphocyte proliferative response to cytochrome c. 8 88

alpha Complementation in beta-galactosidase is the restoration of enzyme activity by addition of the alpha donor CNBr2, from amino acid residues 3--92 of the polypeptide, to inactive M15 protein from the lacZ deletion mutant strain M15. M15 protein lacks residues 11--41 and is a dimer; the active complex, like native beta-galactosidase, is tetrameric [Langley, K. E., & Zabin, I. (1976) Biochemistry 15, 4866--4875]. A dimer--dimer binding region in beta-galactosidase has been identified by proteolytic and immunologic studies of alpha-complementation. Proteolytic experiments were carried out with trypsin. Treatment of native beta-galactosidase with trypsin, followed by reaction of the mixture with cyanogen bromide, yields intact CNBr2 as measured by its ability to complement M15 protein. Active CNBr2 is not obtained when urea-denatured beta-galactosidase is treated in the same way. Therefore the segment corresponding to CNBr2 is apparently buried within the folded protein. Immunologic experiments were carried out with antibodies against CNBr2, tryptic peptide T8 (residues 60--140), and CNBr3 (residues 93--187). Anti-CNBr2 and anti-T8 bind to M15 protein but not to beta-galactosidase, indicating that this area is exposed in the dimer. Anti CNBr2, but not anti-T8 or anti-CNBr3, inhibits the formation of alpha-complemented enzyme. These results indicate that an early part of the sequence, within the segment corresponding to CNBr2, is involved in dimer--dimer interaction.
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PMID:A dimer--dimer binding region in beta-galactosidase. 8 82

In this study, we tried to get information about the fine antigen-binding ability of purified, soluble, idiotype-positive T-cell receptor molecules. Lewis anti-DA T-cell receptors were purified from normal Lewis serum by the use of anti-idiotypic immunosorbent and sodium dodecyl sulfate-polyacrylamide gel, and were coupled to cyanogen bromide-activated Sepharose 4B. In parallel, Lewis anti-DA, Lewis anti-BN, and DA anti-Lewis alloantibody immunosorbents were prepared. The major Ag-B chain (44,000 daltons) and the two polypeptide chains (34,000 and 27,000 daltons) of Ia were purified from Lewis, DA, and BN lymphocytes and absorbent on the above-mentioned immunosorbents. We found that the major Ag-B chain as well as the two Ia chains were bound to the alloantibody columns if they were derived from the corresponding allogeneic strain. No retaining ability for self-major histocompatibility complex (MHC) or third-party MHC chains was noted with the alloantibody immunosorbents. When using immunosorbents made up of idiotypic T-cell receptors, only two MHC polypeptides of the relevant allo-MHC type were retained, namely, the Ag-B and the heavy Ia chains. No detectable activity was observed when testing the same column for reactivity against third-party MHC polypeptide chains. However, the Lewis anti-DA T-cell receptors could be shown to display weak, but significant, reactivity toward one Lewis MHC polypeptide chain, that is, the heavy chain of Ia type.
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PMID:Binding of purified, soluble major histocompatibility complex polypeptide chains onto isolated T-cell receptors. I. Reactivity against allo- and self-determinants. 9 53

The amino acid sequence of staphylococcal protease has been determined by analysis of tryptic peptides obtained from cyanogen bromide fragments. Selected peptides obtained from digests with staphylococcal protease, thermolysin, and chymotrypsin provided the information necessary to align the tryptic peptides and the cyanogen bromide fragments. The protease is a single polypeptide chain of some 250 amino acids and is devoid of sulfhydryl groups. The COOH-terminal tryptic peptide of of the protease molecule contains some 43 residues, most of which are aspartic acids, asparagines, and prolines. The amino acid sequence of this peptide was not determined. The primary structure near the active serine residue indicates that staphylococcal protease is related to the pancreatic serine proteases. However, it has little or no additional sequence homologies with these enzymes except for the regions near histidine-50 and aspartic acid - 91. These regions have striking similarities with the corresponding regions of protease B and the trypsin-like enzyme of Streptomyces griseus.
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PMID:The primary structure of staphylococcal protease. 9 22

The amino acids in 9 cyanogen bromide peptides have been placed in sequence starting from the NH2 terminus. The peptides account for residues 1 to 377 of the whole protein and include the largest (CNBr7, 119 residues) and the smallest (CNBr1, 2 residues) of the cyanogen bromide peptides. This region contains only 3 of the 20 lysine residues in the polypeptide chain. A high proportion of charged groups are present (28 of 66 arginine, 28 of 60 glutamic acid, and 24 of 65 aspartic acid residues).
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PMID:Amino acid sequence of beta-galactosidase. VIII. Sequence of the NH2-terminal segment, CNBr peptides 1 to 9, residues 1 to 377. 9 95


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